1. Field of the Invention
The present invention relates to a transistor in which an oxide semiconductor film containing In, Zn, or Sn is used for a channel region, and relates to a semiconductor device including the transistor. In particular, the present invention relates to a semiconductor device including a logic circuit using the transistor.
2. Description of the Related Art
Patent Document 1 discloses a circuit including a transistor in which an amorphous oxide is used for a channel region. The amorphous oxide contains In—Ga—Zn—O or the like. The transistor is a normally-off type transistor in which the electron mobility is 1 cm2/V·sec or more and current flowing between source and drain when voltage is not applied to a gate electrode (in an off state) (the current also called off-leakage current) is less than 10 microamperes.